Industrial truck



June '1, 1943. R. c; HOWELL 2,320,601

INDUSTRIAL TRUCK Filed Jan. 20, 1943 5 Sheets-Sheet l INVENTOR Roy (5.How-ell BY ATTORNEY June i W43. R. 1c. HOWELL INDUSTRIAL TRUCK FiledJan. 20, 1943 3 Sheets-Sheet 2 BY Roy a on eu- IIIIIIII NW a? ATTORNEYJune 1, 1943.

R. c. HOWELL.

INDUSTRIAL TRUCK Filed Jan. 20, 1943 3 Sheets-Shee't 3 Patented June 1,1943 umreo STATES PATENT OFFICE Application January 20, 1943, Serial No.472,973

12 Claims.

This invention relates'to industrial trucks, and particularly to motordriven trucks of the type having an elevator at the forward end thereof.Industrial trucks of the elevator type are ordinarily provided with avertically movabie carriage having a'load-carrying platform projectingforwardly from the front end of the truck. Such trucks are oftendesigned 'to handle loads weighing many tons. In order to prevent thetruck from overbalancing the entire truck sufiiciently to tilt it aboutthe front axle as a fulcrum or to reduce the load imposed upon the reardriving wheels to such an extent that traction is impaired, it has beencommon practice to add a substantial weight to or build the same intothe rear end of the truck, su'flicient to maintain traction when thetruck is carrying themaximum load. The provision of a counterweight addsto the expense of construction and the additional weight of the truckincreases the cost of operation due to more rapid consumption of fueland v more rapid wear of tires.

It is the object of the present invention to provide a lift truck of thecharacter referred to which is so constructed that counterweighting isunnecessary and which may consequently be of lighter and more economicalconstruction.

More specifically, it is the object of the invention to provide atruck'ha'ving an extensible body or a frame so that the leverage of thetruck body may be increased by increasing its length, so that the truckbody may be adiusted to effectively overbalance any load being handled.

A further object is to provide a simple and conveniently operable meansfor telescoping the truck frame and operating the elevator.

Another advantage of the invention is the fact that the truck willoperate in extremely close quarters when handling relatively lightloads, while it is also possible tame the same truck for handling veryheavy loads when not restricted by space limitations, the truck of thepresent invention being thus adapted to do work which heretofore wouldhave required two trucks of different capacities. 7

With the above and other objects in view, the invention may be said tocomprise the truck as illustrated in the accompanying drawings,hereinafter described and particularly set forth in the appended claims,together with such variations and modifications thereof as will beapparent to one skilled in the art to which the invention pertains.

Reference should be had to the accompanying drawings forming a which:

Figure 1 is a side elevation of a truck embodying the invention, theextended position of the truck frame being shownin dotted lines;

Fig. 2 is a top plan view of the truck;

Fig. 3 is afragmentary central vertical section through the frametelescoping cylinder and the lower portion of the carriage hoistcylinder;

Fig. 4 is a transverse section taken on the line indicated at 4-4 inFig. 1;

Fig. 5 is a fragmentary sectional view on an enlarged scale showing thesliding connection between the front frame section and the side membersof the rear frame section;

Fig. 6 is a diagrammatic view showing the fluid pressure system foroperating the cylinders and wheel-driving motor;

part of this specification, in

Fig. 7 is a sectional view showing the singleaction valve forcontrolling the. hoist cylinder; and Y Fig. 8 is a sectional viewshowing a doubleaction valve such as used for controlling thewheel-driving motor, the frame telescoping cylinder and the tiltingcylinders.

Fig. 9 is a sectional view showing the pressure operated regulatingvalve.

Referring to the accompanying drawings, the truck of the presentinvention has front and rear telescopically connected sections l and 2which are adapted to be adjusted to vary the length of the wheel base.In the embodiment of the invention herein shown, the front section I hasan axle 3 at its forward end upon which the front supporting wheels 4are mounted. The rear end of the truck is supported upon a singletraction I wheel 5, which is mounted on an axle 6 mounted in a'frame I,which is swivelled in the rear frame section 2, a suitable bearing 8being provided between the frame I andthe rear frame section 2. The rearframe section 2 supports an elevated platform 9 directly over thesupporting wheel 5, the platform 9 providing a support for a suitablemotor such as an internal combustion engine III.

Immediately in front of the engine ID, a laterally facing driver's seatH is mounted upon the rear frame section 2 and in front of the seat ismounted a steering wheel [2, which is connected by suitable gearing tothe wheel frame I so that the wheel 5 may be turned to steer the truck.The rear frame section 2 has channel-shaped side frame members l3 whichproject forwardly from the wheel frame bearing 8; the front section Ihas a body in the form of a plate M which has upturned side edgeportions I5, which are adapted to receive the frame members I3 betweenthem and which have inwardly projecting flanges I5 which overlie the topedges of the frame members I3.

Upper and lower wear strips i1 and I8 are interposed between the flangesl6 and the top edge of the frame channels I3 and between the body of theplate I4 and the lower flanges of the channels I3, the strips beingpreferably secured to the flanges l6 and the plate I4. A guide strip I9is detachably secured to the undersides of the flanges I5 inwardly ofthe channel frame members I3 by means of bolts 20. The side framemembers I3 are adapted to slide longitudinally in the front section I topermit extension of the truck frame.

At the front end of the frame section I there is mounted an elevatorguide standard composed of side posts 2| in the form of inwardly facingchannels and a top cross member 22 which connects the upper ends of theposts 2|. The posts 2| are attached at their lower ends to a sleeve 23rotatably mounted upon the axle 3. The guide standard is held invertical position or in positions inclined slightly to the vertical bymeans of cylinders 24 which are pivoted to brackets 25 attached to theflanges I5 rearwardly of the posts 2|, the cylinders 25 having pistons25 pivoted at their forward ends to the posts 2|. When the pistons 25are at their forward limits of movement, the elevator standard is heldnearly in vertical position preferably with about 2 degrees forwardtilt, and the standard may be held in various rearwardly tiltedpositions by means of fluid under pressure in the cylinders 24.

'A carriage 21 is mounted for vertical travel on the guide standard, thecarriage having a forwardly projecting load-carrying platform 24 and therollers 24 which travel on the flanges of he channel posts 2|. A hoistcylinder is mounted on the sleeve 23 between the posts 2| and has apiston 3| carrying a sprocket 32 at its upper end. A sprocket chain 33is attached at one end to-the carriage 21, extends over the sprocket 32and is attached at its opposite ends to a crossbar 34 attached to therear side of posts 2|. By supplying fluid under pressure to the lowerend of the cylinder 34, the sprocket 32 may be elevated to liftthecarriag 21. The cross bar 22 may have its central portion offsetrearwardly, -as shown in Fig. 2, to permit the sprocket 3 2 to'beelevated past the crossbar.

A cylinder 35 is attached at its rear end to the rear frame member 2centrally thereof and has a piston 34 attached to a bracket 31 attachedto the plate I4 of the front frame member. By controlling the deliveryof fluid under pressure to the cylinder 45, the truck frame may beextended or retracted.

The rear suporting wheel 5 is driven by means of a hydraulic motor 34mounted upon the frame 1 and the motor 34, as well as the variouscylinders above referred to, is actuated by fluid m'ain tained underpressure by means of a pump 33 driven by the enginev I4. The fluidpressure sys-' tern is illustrated diagrammatically in Fig. 6. A liquidreservoir 44 is provided on the rear frame member 2 and this liquidreservoir is connected by a pipe 4| to the pump 34." A valve unit 42through which the flow of fluid is controlled to the cylinders 24, 34'and 34, and to the motor 34, is connected to the pump 34 by a pipe 43.

The valve unit 42 has a passage to which the pipe 43 delivers which iscontrolled by a pressure regulating safety valve 44 and which isconnected to the reservoir 44 through a return line 45. The passagethrough the valve unit 42 from the pipe 43 to the return pipe 45 iscontrolled by a spring operated regulating valve 44, which is normallyheld closed by its spring but which opens when a predetermined pressureis imposed upon it to permit liquid to pass through the valve unit 42and return to the reservoir. The setting of the valve 44 determines thepressure maintained in the pipe '43 and in the valve passages by thepump 34.

The return pipe 45 may be provided with a shutoff valve 48 adjacent thebottom of the tank 45 to prevent leakage of liquid from the tank duringrepair of valve or cylinder parts.

The valvev unit 42 has a single-acting valve 41,

such as shown in Fig. '1, for controlling the supply of fluid to thehoist cylinder 30 and provided with three identical double-acting valves45, 44a and 48b, such as shown in Fig.-8, for controlling the motor 38and cylinders 25 and 35. A single pipe 49 connects the valve 41 with thecylinder 34 and this pipe has a flexible section 43a which is ofsufficient length to permit the extension of the truck body and which isadapted to bow laterally when the front frame section of the truck isretracted. Pipes 54 and 5| connect the hydraulic motor 33 to the valve44, pipes 53' and 53 connect the valve 48:! to the tilt cylinders 24,and pipes 54 and 55 connect the valve 44b to the frame telescopingcylinder 35. The pipe 52 has branches leading to the upper ends of thetwo cylinders 24 and the pipe 53 has branches leading to the lower endsof the two cylinders, the branch pipes being provided with flexiblesections 5211 and 5341. which permit the movement of the cylinders 24with the frame section I toward or away from the valve unit 42, which ismounted upon the rear frame section 2. As shown in Fig. 2, the flexiblepipe sections lie upon the plate I4 and are adapted to be bowed when thefront frame section I is retracted and to be straightened as the frontframe section I is extended.

. The propelling motor 34 is controlled by means I of a pedal 54convenient to an operator sitting on the seat I I, the pedal 54 beingconnected by a 53 for controlling the flow from the pressure line 43 tothe motor 34 and from the motor 34 to the return line 45'.

In the position shown in Fig. 8. ports 44 and 55 leading to pipes 54 and5| are both closed. By

moving the valve member 54 downward from the position shown in Fig. 8,the pressure line 43 may be connected to the port 44 leading to thepipe. 54 and the pipe 5| may be connected throulh the port 45 to thereturn line 45. Upon upward movement from the position shown, thepressure line 43 may be connected through a by-pass 44 to the port 45and pipe II and pipe llmnnected through the port 44 to the return line45. Thus, the rocking movement of the pedal 54 may causethe. motor 44 tobe driven in a forward or rear- ,ward direction as desired. Byregulating the movement of the pedal 54. the ports 44 and, 45 maybegradually opened and closed to regulate the rate of flow to the motor 34to vary the speed at which the truck is propelled or to restrict theflow to effect a braking acti The valves 44a and 44b controlling thecylin- 2,320,601 ders 24 and 35 are identical with the valve controllingthe motors 38 and are operated to tilt the elevator guide standard or totelescope the frame members by means of hand levers 61 and 68, which areconnected by links 69 and to levers 1| and 12, which are identical withthe lever 58 above described, the levers 61 and 68 being mounted withinconvenient reach of an operator seated on the seat H. The pistons of thecylinders 24 and 35 may be locked in any desired position to hold theguide standard at the desired inclination or to hold the extensibletruck body in adjusted position by moving handles 61 or 68 to neutral orvalve closing position.

The flow of fluid to the hoist cylinder 30 is controlled by a hand lever13 connected by a link 14 to a lever 15 pivoted to the valve unit 42.The lever 15 raises and lowers a vertical valve member 16 which fits ina vertical bore 11 in the valve 41. As shown in Fig. 7, the valve member16 has spaced grooves 18 and 19 which are adapted to register with thepressure and return lines 43 and 45 and with an intermediate port 80which communicates with the pipe 49 leading to the cylinder 30. In theposition shown in Fig. 7, the port 80 is closed. By moving the member 16downwardly, the pressure line 43 may be connected to the port 80 todeliver fluid under pressure to the hoist cylinder by moving the member15 upwardly from the position shown in Fig, 7, the port 80 may be placedin communication with the return line. to permit the fluid to flow fromthe hoist cylinder 30 to the reservoir 40. The rate of flow of fluid toor from the cylinder 30 may be varied to regulate the speed of ascent ordescent of the carriage 21 by adjusting the valve members 16 and thecarriage 21 may be held in any position of vertical adjustment by movingthe member 16 to port closing position.

All controls being disposed conveniently to the seal II, the operatormay control the propulsion of the vehicle by means of the pedal 56 andthe tilting of the guide standard, the telescoping of the frame and theraising and lowering of the load by means of the levers 61, 68 and 13,each of the levers being movable in either direction from a neutralposition for forward or reverse What I claim is: l 1. An industrialtruck having front and rear telescopically connected wheel supportedframe sections, an elevator on the front section havingmeans forsupporting a load forwardly of the supporting wheels of said section,and independently controlled means carried by the truck for propellingthe same, for telescoping said sections and for operating said elevator.

2. An industrial truck having front and rear telescopically connectedwheel supported frame sections, an elevator on the front section having7 means for supporting a load forwardly of the vsupporting wheels ofsaid section, a motor mounted on the rear section, and mechanismspowered by said motor for propelling the truck, telescoping. saidsections and operating said elevator.

operation. The valves operated by the levers 61,

to retainthe fluid in the in neutral position,

68 and 13 are closed cylinders when the levers are so that the partsactuated by the cylinders may be held in adjusted positions. Thus thetruck may be retained in any desired extended position, the guidestandards at any desired height.

To avoid strain on the pipe lines due to the bowing of the flexiblepipesections when the frame is telescoped, pipes 52 and 63 are preferablyconnected to the flexible sections 62a, 581; through an anchor block llflxed to the rear frame section 2. The flexible section 48a of the pipe4! is preferably connected at its ends to anchor blocks 82 and 83 fixedto the front and rear sections l and 2. Since the pipe I is somewhatlarger than the pipes 52 and 53 the anchor blocks 82 and. 83 arepreferably placed as far apart as they can conveniently be placed sothat th length of the flexible section 48a is sumcient to avoid sharpbending of the conduit-when the front section is retracted.

It will be understood that modifications of the construction shown maybe resorted to without departing from the spirit of this invention asdefined in the appended claims.

sections and for operating said elevator, and

means operably connecting said pump and cylinders.

4.An industrial truck having front and rear telescopically connectedwheel supported frame sections, a guide standard at the forward end ofthe front section, an elevator carriage mounted on said standard andhaving a forwardly projecting load platform, means carried by the rearsection for propelling and steering the truck, and power operated meanscarried by the truck for telescoping said frame sections and forhoisting said carriage.

5. An industrial truck having front and rear telescopically connectedwheel supported frame sections, a pivotally mounted guide standard atthe forward end of the front section, an elevator carriage mounted onsaid standard and, having means for supporting a load forwardlyof thefront wheels, a'motor mounted on the rear section, and mechanismspowered by said motor for propelling the truck, telescoping saidsections, tilting said standard and hoisting said carriage.

6. An industrial truck comprising a rear frame section, a supportingwheel for said frame section swivelled to swing about a vertical axis, a

front frame section telescopically connected with section, a supportingwheel for said frame section swivelled to swing about a vertical axis, afront frame section telescopically connected with the rear frame sectionand having a cross member at its forward end, supporting wheels atopposite ends of said cross member. a steering gear connected to saidswivelled wheel, a guide stand ard pivoted to said cross member. anelevator carriage mounted on said standard, a motor mounted on said rearsection, and mechanisms powered by said motor for driving said swivelledwheel, telescoping said sections, tilting said standard and hoistingsaid carriage.

8. An industrial truck comprising a rear frame section, a supportingwheel for said frame sec- ,tion swivelled to swing about a verticalaxis, a

front frame section telescopically connected with the rear frame sectionand having a cross member at its forward end, supporting wheels atopposite ends of said cross member, a steering gear connected to saidswivelled wheel, a guide standard pivoted to said cross member, anelevator carriage mounted on said standard, a motor mounted on said rearsections, means for operating said carriage comprising a hoist cylindermounted on said cross member, means for tilting said standard comprisinga cylinder pivoted to the front frame section rearwardly of the standardand having a piston pivoted to said standard, a fluid pressure systemfor operating said cylinders including a pump on said rear section,conduits connecting the pump and cylinders, control valves and a motorfor driving said pump, and means for telescoping said sections.

9. An industrial truck comprising telescopically connected front andrear wheel supported sec tions, the front section having an axle at itsfor- 'ward ends provided with supporting wheels at its opposite ends, aguide standard pivoted to said axle, an elevator carriage mounted onsaid standard, a hoist cylinder mounted on the front section andconnected to said carriage, a tilt cylinder pivotally connected to saidfront section rearwardly of the standard and having pistons pivotallyconnected to the standard, a cylinder mounted on the rear section anddisposed longitudinally thereof, the latter cylinder having a pistonconnected to the front section, and a fluid pressure system foroperating said cylinders including pressure creating means mounted onthe rear section and conduits connecting said means to the cylinders,the conduits connected to the cylinders on the front section havingflexible portions adapted to be bowed when the front section isretracted and to be straightened when the front section is extended.

10. An industrial truck having a rear frame member having a'supportingwheel swivelled to swing about a vertical axis, a platform overlyingsaid wheel and forwardly extending side frame members, a front framesection having side portions telescopically engaging the side members ofsaid rear section, supporting wheels and a guide standard at the forwardend of the front section, an elevator carriage on said standard, a motormounted on said platform, a pump driven by said motor, and mechanismsoperated by fluid maintained under pressure by said pump for drivingsaid swivelled wheel, telescoping said sections, and hoisting saidelevator carriage.

11. An industrial truck having a rear frame member having a supportingwheel swivelled to swing about a vertical axis, a platform overlyingsaid wheel and forwardly extending side frame members, a front framesection having side portions telescopically engaging the side members ofsaid rear section, supporting wheels and a guide standard at the forwardend of the front section, an elevator carriage on said standard, a motormounted on said platform, a pump driven by said motor, cylinders fortelescoping said frame sections and for hoisting said carriage, conduitsconnecting said cylinders with said pump, andvalves for controlling theoperation of said cylinders.

12. An industrial truck having'a rear frame member having a supportingwheel swivelled to swing about a vertical axis, a platform overlyingsaid wheel and forwardly extending side frame members, a front framesection having side portions telescopically engaging the side members ofsaid rear section, supporting wheels and a guide standard at the forwardend of the front section, an elevator carriage on said standard, a motormounted on said platform, a pump driven by said motor, cylinders forhoisting said carriage and tilting said standard mounted on said frontsection, conduits connecting said cylinders with said conduits includingelongated flexible sections connected to said cylinders, supportingmeans for said flexible conduit sections, and valves for controlling theoperation of said cylinders.

ROY C. HOWELL.

